Hematuria is the medical term for blood in the urine. Blood in the urine can come from the kidney (where urine is made) or anywhere in the urinary tract (figure 1). The urinary tract includes the ureters (the tubes from the kidneys to the bladder), the bladder (where urine is stored), and the urethra (the tube from the bladder to the outside of the body).

Although seeing blood in the urine can be very frightening, most of the time hematuria in children is not life threatening.

TYPES OF HEMATURIA

There are two main types of hematuria:

●Gross hematuria — Gross hematuria means that blood can be seen in the urine with the naked eye because it turns the urine pink, red, or tea-colored. If you see blood in your child's urine, you should call your child's healthcare provider.

●Microscopic — Microscopic hematuria means that the urine is normal in color, but it has an increased number of red blood cells (blood) as seen with a microscope. If your child's urine dipstick shows blood in the urine, the urine should be examined with a microscope to confirm that blood is present. (See 'What tests will be done?' below.)

HEMATURIA CAUSES

Some common causes of blood in the urine include:

●Bladder (also called urinary tract) or kidney infections

●Kidney stones

●Irritation of the urethra (the area where the urine exits the body)

●Trauma (for example, after falling off a bike and bruising a kidney)

●Vigorous exercise

●Kidney diseases

Less common causes of blood in the urine include certain medications, inherited kidney diseases, and other underlying medical problems. Cancers of kidney or urinary tract that cause hematuria in adults are very rare in children.

Sometimes, the urine appears to have blood in it because other red substances are contained in the urine. This can be seen when children eat an excessive amount of beets (called beeturia), food dyes, or with certain medications (such as phenazopyridine/Pyridium).

HEMATURIA SYMPTOMS

Hematuria may not cause any symptoms. This section will describe the symptoms of some of the most common reasons for hematuria.

●Kidney diseases — Children with kidney diseases can have a variety of symptoms, such as weakness, high blood pressure, puffiness around the eyes, joint swelling, abdominal pain, pale skin, skin rashes, or seizures.

●Depending upon the amount of bleeding, a clot may form in the bladder, which may cause obstruction to the flow of urine.

WHAT TESTS WILL BE DONE?

The evaluation of a child with hematuria depends upon the type of hematuria (microscopic or gross) and the child's recent history, symptoms, and physical examination.

●If the child has microscopic hematuria, but has no symptoms (pain, fever, recent trauma) and no protein in the urine, a urine test will be repeated several times over a few months to determine if the blood persists. No further testing is needed. Urine calcium may also be checked to see if there is an increased amount of calcium in the urine.

If the microscopic hematuria does not resolve, but the child has no symptoms and no protein in the urine, the child will be monitored over time. The child may be referred to a pediatric nephrologist (kidney specialist) if hematuria persists.

●If the child has hematuria and has symptoms of a bladder or kidney infection, testing will be done to confirm the diagnosis. This usually includes a urine culture.

●If the child has hematuria and symptoms suggestive of a kidney stone, testing with an ultrasound or computed tomography (CT) scan of the kidney is performed to confirm the presence of a kidney stone. A urine sample will be collected over 24 hours to measure substances that cause kidney stones.

●If the child has had a recent injury, an imaging test may be recommended to examine the kidneys, ureters, and bladder.

●If the child has hematuria and protein in the urine, further testing will be done. This includes blood and urine tests to evaluate the child's kidney function. The child's blood pressure will also be measured because high blood pressure is a common finding in children with kidney problems. The child may be referred to a pediatric nephrologist if the tests are abnormal.

Family members of children with persistent hematuria may also be tested. Familial hematuria, which has no serious long-term effects, is the most common cause of persistent microscopic hematuria in children.

Your child's healthcare provider is the best source of information for questions and concerns related to your child's medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

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